up.c #include <stdio.h> #include <stdlib.h> #define DIM 2 // square lattice #define NDIR (2*DIM) int L; // grid size int nsite; // = (L+1)^2 int *f_visited; // 0/1 = un/occupied int *nnp; // neighbour index int drvec[NDIR][DIM] = { {-1,0}, {0,-1}, {1,0}, {0,</stdlib.h></stdio.h>…